Loudness control with metadata support

摘要

Loudness control regulations, such as the recent CALM Act (Commercial Advertisement Loudness Mitigation), are being put in place to address consumer complaints about disturbing loudness differences between TV programs and commercials. Fraunhofer's AAC family of audio codecs, including AAC and HE-AAC, now offer the ability to carry the original broadcast metadata to meet the requirements of the CALM Act. This audio metadata technology provides broadcasters with a reliable option to solve loudness issues when existing ATSC broadcast signals are translated to AAC for transmission over cable or satellite networks to consumer's homes. The technology also allows for loudness and dynamic range control for ATSC-M/H Mobile DTV transmissions using HE-AAC. The AAC family of codecs has included broadcast metadata support since their standardization in 1999-2004. However, only with the introduction of metadata translation software, such as Fraunhofer's Metadata Transcoder, has it been possible to convert ATSC A/52 metadata into the AAC format.